1. Field of the Invention
The present invention relates to a film forming method and a film forming system each for forming a coating film composed of an insulating film on a substrate such as an LCD substrate and a semiconductor wafer, for example.
2. Description of the Related Art
In processes of semiconductor device (hereinafter, referred to as xe2x80x9cwaferxe2x80x9d) fabrication, an insulating film is formed on the front face of the wafer, for example, by an insulating film forming system. When an insulating film is formed in the insulating film forming system, a wafer is transferred from a carrier station to a processing section, and a predetermined coating solution for forming the insulating film is applied onto the wafer in a coating apparatus provided in the processing section. Subsequently, the wafer is transferred to a heat processing apparatus and subjected to processing for vaporizing a solvent in the coating solution. Thereafter, this wafer is combined with a predetermined volume of wafers to be put into an annealing furnace collectively. Then, the wafer is subjected to cure processing in the annealing furnace, whereby an insulating film such as an SOG film or the like, for example, is formed on the front face of the wafer.
Recently, with improvements in the wafer materials, a coating solution on the wafer reacts with oxygen more subtly, and therefore it has been desired that the wafer is processed in a lower oxygen atmosphere until cure processing in the annealing furnace. However, in the aforesaid insulating film forming system, since the wafer is exposed in the surrounding air in the heat processing apparatus for vaporizing the solvent in the coating solution and when transferred from the heat processing apparatus to the annealing furnace, the coating film on the wafer is susceptible to reacting with oxygen in the air resulting in occurrence of insufficient insulation or the like in the wafer.
Meanwhile, there is a damascene method in which a predetermined trench is formed in the formed insulating film in advance, a conductive wiring material is buried inside the trench, and the wiring material heaped outside the trench is removed by a CMP (chemical mechanical polishing) technique to thereby form a wiring. A wiring technique referred to as a dual damascene method as one of damascene methods is a technique that both a connecting hole and a trench for wiring previously formed in a layer insulating film are simultaneously buried with a wiring material to thereby form a connecting plug and a wiring simultaneously.
In the case where a semiconductor device is fabricated using the dual damascene method, there is a technique using a laminated layer of an inorganic insulating film and an organic insulating film as a layer insulating film between wirings in order to speed up the semiconductor device. Such inorganic insulating film used for the layer insulating film is generally formed by a plasma CVD method and the organic insulating film is formed by a spin coating.
However, there is a disadvantage that the formation of the inorganic insulating film by the CVD method and the organic insulating film by the spin coating requires a CVD apparatus and a coating apparatus by the spin coating which are completely different in structure, resulting in increased apparatus cost.
An object of the present invention is to form a coating film on a substrate and to retard a reaction between the coating film on the front face of the substrate and oxygen until the coating film is subjected to cure processing in an insulating film forming process.
Moreover, another object of the present invention is to provide a film forming method low in apparatus cost in a film forming method for forming a multi-layered film including an inorganic insulating film and a film forming system of the same.
To achieve the above objects, a first aspect of the present invention is a film forming method comprising the steps of: supplying a first coating solution onto a substrate to form a first coating film; and supplying a second coating solution onto the first coating film to form a second coating film, at least one of the first coating film and the second coating film being an inorganic film.
A second aspect of the present invention is a film forming method comprising the steps of: applying an organic insulating film material onto a substrate by a spin coating to form an organic insulating film; applying an inorganic insulating film material onto the applied organic insulating film material by a spin coating to form an inorganic insulating film; patterning the organic insulating film and the inorganic insulating film using a photolithography method to form a concave portion; and burying a conductive material in the concave portion to form a conductive layer.
A third aspect of the present invention is a film forming method comprising the steps of: applying an organic insulating film material onto a substrate by a spin coating to form a first organic insulating film; applying an inorganic insulating film material onto the applied organic insulating film material by a spin coating to form a second inorganic insulating film; applying an organic insulating film material onto a substrate by a spin coating to form a third organic insulating film; applying an inorganic insulating film material onto the applied organic insulating film material by a spin coating to form a fourth inorganic insulating film; patterning the third organic insulating film and the fourth inorganic insulating film using a photolithography method to form a first concave portion; patterning the first organic insulating film and the second inorganic insulating film using a photolithography method to form a second concave portion; and burying a conductive material in the first concave portion and the second concave portion to form a conductive layer.
A fourth aspect of the present invention is a film forming system comprising: a first coating apparatus for applying a first insulating film material onto a substrate; and a second coating apparatus for applying a second insulating film material onto the first insulating film material, the first insulating film material or the second insulating film material being an inorganic insulating film material.
A fifth aspect of the present invention is a film forming system comprising: a coating apparatus for supplying a coating solution to a substrate to form a coating film; a first heating apparatus for vaporizing a solvent component from the applied coating solution; a second heating apparatus for performing thermal processing for the substrate from which the solvent component has been vaporized in the first heating apparatus; and a delivery section for delivering the substrate between the first heating apparatus and the second heating apparatus, wherein the inside of a processing chamber of the first heating apparatus can be set at an atmosphere lower in oxygen than the surrounding air.
A sixth aspect of the present invention is a film forming system comprising: a coating apparatus for supplying a coating solution to a substrate to form a coating film; a first heating apparatus for vaporizing a solvent component from the applied coating solution; a second heating apparatus for performing thermal processing for the substrate from which the solvent component has been vaporized in the first heating apparatus; and a delivery section for delivering the substrate between the first heating apparatus and the second heating apparatus, wherein an area in which the second heating apparatus and the delivery section are disposed can be set at an atmosphere lower in oxygen than the surrounding air.
A seventh aspect of the present invention is a film forming system comprising: a coating apparatus for supplying a coating solution to a substrate to form a coating film; a first heating apparatus for vaporizing a solvent component from the applied coating solution; a second heating apparatus for performing thermal processing for the substrate from which the solvent component has been vaporized in the first heating apparatus; and
a delivery section for delivering the substrate between the first heating apparatus and the second heating apparatus, wherein an area in which the second heating apparatus and the delivery section are disposed and the inside of a processing chamber of the first heating apparatus can be set at an atmosphere lower in oxygen than the surrounding, air.
According to the present invention, each of an insulating film and a hard mask is formed, for example, by applying a coating solution, so that it is unnecessary to provide a CVD apparatus, resulting in simplification of processes when the two-layered structure is formed.
Moreover, since the two-layered structure of an insulating film and a hard mask layer is formed sequentially by one apparatus including a first coating unit for applying a coating solution for an insulating film and a second coating unit for applying a coating solution for a hard mask, it is unnecessary to transfer the substrate to another apparatus, so that the film-forming processing can be remarkably simplified and thus the insulating film and the hard mask layer can be very speedily formed.
According to the present invention, since the inside of a processing chamber of the first heating apparatus, for example, can be set at a low-oxygen atmosphere, the inside of the processing chamber can be brought to a low-oxygen atmosphere as required. Accordingly, it becomes possible that the substrate carried into the processing chamber is subjected to heat processing in a low-oxygen atmosphere. Consequently, oxidation of the coating film applied on the substrate in the coating unit in reaction with oxygen is prevented.
According to the present invention, in the case where a wiring and a connecting plug are formed in a layered film of an organic insulating film and an inorganic insulating film through a dual damascene process, for example, since both the organic insulating film and the inorganic insulating film are formed using a spin coating, an apparatus such as a CVD apparatus becomes unnecessary, thereby greatly reducing fabricating apparatus cost. Moreover, an insulating film that is excellent in low dielectric constant characteristic and is good in adherence between the organic insulating film and the inorganic insulating film can be formed.